All seven-digit telephone numbers in a town begin with 555. How many telephone numbers may be assigned in the town if the last four digits do not begin or end in either a zero or a one?
Please help? Can someone explain how to do this?
Help with Probability?
2015-09-16 2:03 am
回答 (1)
2015-09-16 2:47 am
✔ 最佳答案
8 choices for the first digit10 choices for 2nd
10 choices for 3rd
8 choices for last
Product of above
6400
收錄日期: 2021-05-02 11:16:12
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https://hk.answers.yahoo.com/question/index?qid=20150915180328AAqQizj